The invention relates in general to fuel injectors for internal combustion engines and in particular to fuel injectors that include an orientation feature for orienting the fuel injector with respect to the manifold or head of the engine.
Engine emission requirements have driven the need to achieve better targeting of the fuel spray as it exits a fuel injector. The ability to maintain a consistent and accurate fuel spray targeting at the intake valve depends, among other things, on the stack up of tolerances between the injector fuel orientation and the intake valves.
In the past, the feature that maintains orientation of top feed fuel injectors with respect to the intake valves was located at the fuel inlet end of the injector. Typically, the orientation feature was part of the overmold. The orientation feature on the overmold mated with an orienting clip. The orienting clip mated with an orienting cup on the fuel rail. Such an arrangement is shown, for example, in U.S. Pat. No. 5,803,052 issued on Sep. 8, 1998 to Lorraine et al. The aforementioned U.S. Patent is hereby expressly incorporated by reference.
Thus, in the prior art, the various tolerances between the injector fuel orientation and the intake valves included the tolerance on the injector between the fluid orienting disc and the fuel inlet end, the tolerance between the fuel inlet overmold and the clip, the tolerance between the clip and the rail cup, the tolerance between the rail cup and the rail body, the tolerance between the rail body and the brackets, the tolerance between the brackets and the screw, the tolerance between the screw and the hole in the manifold or head, and the tolerance between the screw hole boss and the intake valves.
Because of the large number of components and tolerances involved, it was difficult to obtain precise targeting of the fuel spray.